Function of Respiration SBI3U

RESPIRATORY SYSTEM PRIMARY function: BREATHING (for gas exchange): 1.uptake oxygen needed by the cells 2.release carbon dioxide produced by the cells (remove waste, pH balance of blood) Also used to produce SOUND

Why do we need to breath oxygen? Think of your previous digestive unit! cellular respiration: glucose + oxygen = carbon dioxide and water

HUMAN ADAPTATIONS For efficient gas exchange to occur: 1.Water must be present at the respiratory surface. Adaptation: Human lung located within the body cavity which contains a lot of water and air is moistened when it enters lungs. (Compare this to worm, fish, frog, insect…)

Types of respiration in animals

Outer skin –Earthworm Gills –Fish Treacheal System –Insects Lungs –Land animals

Why is this scenario physiologically impossible?

HUMAN ADAPTATIONS 2.The respiratory surface must be large Adaptation: Spread out on a flat surface the gas- exchange surface is how big? a)Half of a basketball court b)Half of a tennis court c)Ping pong table

The Human Respiratory System Nasal cavity Path taken by air Path taken by food

The Human Respiratory System PartFunctionSpecial Features Nasal passages Point of entry Filter, warm, moisten air Mucus, hairs, many capillaries, sinus cavities, turbinates Oral Cavity Warm and moisten air Alternate space for gas exchange, no filtration

The Human Respiratory System Nasal Cavity Path taken by air Path taken by food Pharynx Epiglottis Esophagus

The Human Respiratory System PartFunctionSpecial Features Pharynxconnects nasal and oral cavity to larynx Cilia in top portion move food towards mouth to be swallowed EpiglottisA flap that prevents food from entering the lungs by blocking the glottis (opening of trachea) Small, flexible

The Human Respiratory System Nasal Cavity Path taken by air Path taken by food Pharynx Epiglottis Esophagus Trachea Larynx Upper Respiratory Tract

The Human Respiratory System PartFunctionSpecial Features LarynxContains the vocal cords – for sound, “voice box” “Adam’s Apple” two flaps of cartilage, vibrate when air passes through TracheaPassage of air into 2 bronchi, “windpipe” filter particles up to mouth ~12cm long -Semicircular cartilage rings to prevent collapse - Cilia and mucus

The Human Respiratory System Nasal Cavity Path taken by air Path taken by food Pharynx Epiglottis Esophagus Trachea Bronchi Bronchioles Larynx Upper Respiratory Tract

The Human Respiratory System PartFunctionSpecial Features BronchusEach carries air into lungs and splits into many bronchioles Full cartilage rings for support BronchioleMany branches carry air to alveoli Able to change diameter to regulate air flow Many branched tubes, Smallest passageways, to increase surface area Smooth muscle walls NO cartilage rings

The Human Respiratory System Nasal Cavity Path taken by air Path taken by food Pharynx Epiglottis Esophagus Trachea Bronchi Bronchioles Alveoli Diaphragm Larynx Upper Respiratory Tract Lower Respiratory Tract

The Human Respiratory System PartFunctionSpecial Features Alveoli (singular: alveolus) Site of external respiration (gas exchange) ~150 million very thin tiny sacs (large surface area) Single cell layer thick, surrounded by capillaries Coated with “surfactant” (a lipoprotein) to prevent sticking DiaphragmIncreases and decreases volume of chest cavity Dome shaped, thin, muscular

The Human Respiratory System PartFunctionSpecial Features Pleural Membrane Surrounds lungs and lines chest cavity, reduces friction Filled with fluid that reduces friction during inhalation